Hi there,
Some thoughts:

What dates of birth for the babies born 1886 at Bailieston Victoria and 1887 Liverpool NSW, perhaps John was not around for these births?
http://srwww.records.nsw.gov.au/indexes/searchform.aspx?id=40&new=1 John SPENCE 1886-7 was in Parramatta district and having troubles with the police. Two sentences, firstly in Parramatta Gaol for six months, then Darlinghurst Gaol with Hard Labour 18 months, concurrent with former sentence. (So 18 months ‘all up’)
http://trove.nla.gov.au/ndp/del/article/28348009 SMH 7 May 1887
Darlinghurst Admissions
No. 3871 John SPENCE, born United States of America, 1853, arrived in the colony (of NSW) on the ship ‘Drover’ (no year stated). Trade or occupation previous to conviction GARDENER, C of E, can read and write, 6ft 1 inch, 168 lbs, Brown hair, Brown eyes, (bushy moustache in photo)
Tried Parramatta QS on 6 May 1887, False Pretences, 18 months HL

Some earlier threads
http://www.rootschat.com/forum/index.php?topic=508057.0http://www.rootschat.com/forum/index.php?topic=607841.0

Some thoughts about the two photos
At State Records NSW website, Photo Investigator, ENTER “Hill End” and find the photos of the Hill End Court House, and look to the right of that to the Iron roofed house. (4346_a020_a020000030.jpg) and then keep looking for the Hill End Post Office. Last time I checked, the Hill End Post Office was still standing. I am fairly certain that there were mature Norfolk Island Pines standing at Hill End when I was last in that district (several years ago). I am not sure when they were planted.
http://www.nationalparks.nsw.gov.au/hill-end-historic-site/village-walking-track/walking Looking at the first house (two men standing outside one corner of the building) it is likely to be two rooms wide, with the main entrance directly in front of the front steps, and opening up into a hallway. The side door room is accessed via the same front steps and the length of the main building is about the same as the width, so two rooms deep too. So, to me, it is not actually a wealthy pastoralist’s homestead. Also, neither of the chaps standing on that corner seem to me to be over 6ft tall…. To me they are standing on the public footpath outside the building, which is what has prompted me to look at the public buildings at Hill End. Of course, it is likely that I am way off track. But perhaps the SRNSW Photo Investigator link may be of help as they have tens of thousands of photographs available for viewing online. I am suggesting you look at Hill End to find good examples of the 1880s era in that part of NSW, it was a long way from Coolah to Hill End in that pre motor car era. I have no understanding of Victoria in that era. Anyways, here’s the link, and may I suggest you just type in the township names and scroll through the photos that turn up. Hill End is basically a National Trust Site
http://investigator.records.nsw.gov.au/asp/photosearch/ Cheers, JM